This invention relates to an automatic sputtering apparatus for successively carrying out sputtering to form a layer on a substrate.
As will later be described with reference to one of a few figures of the accompanying drawing, a conventional automatic sputtering apparatus comprises a sputtering or main chamber for carrying out sputtering and a preliminary chamber for preliminarily processing a substrate prior to introducing the substrate into the sputtering chamber. The preliminary and the sputtering chambers are usually coupled to each other through a gate valve interposed therebetween and to inlet and outlet chambers coupled to the preliminary and the main chambers, respectively.
In the conventional sputtering apparatus, the preliminary chamber is kept at a higher pressure than the sputtering chamber during automatic operation of the apparatus. As a result, when the gate valve is opened after completion of preliminary processing, impurity gases, such as vapor, oxygen, and nitrogen, which are inevitably produced during the preliminary processing, flow into the sputtering chamber together with the substrate subjected to the preliminary processing. Such impurity gases contaminate a gas filled in the sputtering chamber and considerably deteriorate quality of a layer formed on each substrate.
It may be possible to avoid an adverse affect of the impurity gases if the gate valve is manually controlled. However, manual control of the gate valve is difficult to carry out and is not suitable for automatically and successively processing a great number of substrates at a high speed.